linux/fs/ext2/inode.c

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/*
* linux/fs/ext2/inode.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Goal-directed block allocation by Stephen Tweedie
* (sct@dcs.ed.ac.uk), 1993, 1998
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*
* Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
*/
#include <linux/smp_lock.h>
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/module.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include "ext2.h"
#include "acl.h"
#include "xip.h"
MODULE_AUTHOR("Remy Card and others");
MODULE_DESCRIPTION("Second Extended Filesystem");
MODULE_LICENSE("GPL");
static int ext2_update_inode(struct inode * inode, int do_sync);
/*
* Test whether an inode is a fast symlink.
*/
static inline int ext2_inode_is_fast_symlink(struct inode *inode)
{
int ea_blocks = EXT2_I(inode)->i_file_acl ?
(inode->i_sb->s_blocksize >> 9) : 0;
return (S_ISLNK(inode->i_mode) &&
inode->i_blocks - ea_blocks == 0);
}
[PATCH] ext2 corruption - regression between 2.6.9 and 2.6.10 Whilst trying to stress test a Promise SX8 card, we stumbled across some nasty filesystem corruption in ext2. Our tests involved creating an ext2 partition, mounting, running several concurrent fsx's over it, umounting, and fsck'ing, all scripted[1]. The fsck would always return with errors. This regression was traced back to a change between 2.6.9 and 2.6.10, which moves the functionality of ext2_put_inode into ext2_clear_inode. The attached patch reverses this change, and eliminated the source of corruption. Mingming Cao <cmm@us.ibm.com> said: I think his patch for ext2 is correct. The corruption on ext3 is not the same issue he saw on ext2. I believe that's the race between discard reservation and reservation in-use that we already fixed it in 2.6.12- rc1. For the problem related to ext2, at the time when we design reservation for ext3, we decide we only need to discard the reservation at the last file close, so we have ext3_discard_reservation on iput_final- >ext3_clear_inode. The ext2 handle discard preallocation differently at that time, it discard the preallocation at each iput(), not in input_final(), so we think it's unnecessary to thrash it so frequently, and the right thing to do, as we did for ext3 reservation, discard preallocation on last iput(). So we moved the ext2_discard_preallocation from ext2_put_inode(0 to ext2_clear_inode. Since ext2 preallocation is doing pre-allocation on disk, so it is possible that at the unmount time, someone is still hold the reference of the inode, so the preallocation for a file is not discard yet, so we still mark those blocks allocated on disk, while they are not actually in the inode's block map, so fsck will catch/fix that error later. This is not a issue for ext3, as ext3 reservation(pre-allocation) is done in memory. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 22:25:45 +00:00
/*
* Called at each iput().
*
* The inode may be "bad" if ext2_read_inode() saw an error from
* ext2_get_inode(), so we need to check that to avoid freeing random disk
* blocks.
*/
void ext2_put_inode(struct inode *inode)
{
if (!is_bad_inode(inode))
ext2_discard_prealloc(inode);
}
/*
* Called at the last iput() if i_nlink is zero.
*/
void ext2_delete_inode (struct inode * inode)
{
truncate_inode_pages(&inode->i_data, 0);
if (is_bad_inode(inode))
goto no_delete;
EXT2_I(inode)->i_dtime = get_seconds();
mark_inode_dirty(inode);
ext2_update_inode(inode, inode_needs_sync(inode));
inode->i_size = 0;
if (inode->i_blocks)
ext2_truncate (inode);
ext2_free_inode (inode);
return;
no_delete:
clear_inode(inode); /* We must guarantee clearing of inode... */
}
void ext2_discard_prealloc (struct inode * inode)
{
#ifdef EXT2_PREALLOCATE
struct ext2_inode_info *ei = EXT2_I(inode);
write_lock(&ei->i_meta_lock);
if (ei->i_prealloc_count) {
unsigned short total = ei->i_prealloc_count;
unsigned long block = ei->i_prealloc_block;
ei->i_prealloc_count = 0;
ei->i_prealloc_block = 0;
write_unlock(&ei->i_meta_lock);
ext2_free_blocks (inode, block, total);
return;
} else
write_unlock(&ei->i_meta_lock);
#endif
}
static int ext2_alloc_block (struct inode * inode, unsigned long goal, int *err)
{
#ifdef EXT2FS_DEBUG
static unsigned long alloc_hits, alloc_attempts;
#endif
unsigned long result;
#ifdef EXT2_PREALLOCATE
struct ext2_inode_info *ei = EXT2_I(inode);
write_lock(&ei->i_meta_lock);
if (ei->i_prealloc_count &&
(goal == ei->i_prealloc_block || goal + 1 == ei->i_prealloc_block))
{
result = ei->i_prealloc_block++;
ei->i_prealloc_count--;
write_unlock(&ei->i_meta_lock);
ext2_debug ("preallocation hit (%lu/%lu).\n",
++alloc_hits, ++alloc_attempts);
} else {
write_unlock(&ei->i_meta_lock);
ext2_discard_prealloc (inode);
ext2_debug ("preallocation miss (%lu/%lu).\n",
alloc_hits, ++alloc_attempts);
if (S_ISREG(inode->i_mode))
result = ext2_new_block (inode, goal,
&ei->i_prealloc_count,
&ei->i_prealloc_block, err);
else
result = ext2_new_block(inode, goal, NULL, NULL, err);
}
#else
result = ext2_new_block (inode, goal, 0, 0, err);
#endif
return result;
}
typedef struct {
__le32 *p;
__le32 key;
struct buffer_head *bh;
} Indirect;
static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
p->key = *(p->p = v);
p->bh = bh;
}
static inline int verify_chain(Indirect *from, Indirect *to)
{
while (from <= to && from->key == *from->p)
from++;
return (from > to);
}
/**
* ext2_block_to_path - parse the block number into array of offsets
* @inode: inode in question (we are only interested in its superblock)
* @i_block: block number to be parsed
* @offsets: array to store the offsets in
* @boundary: set this non-zero if the referred-to block is likely to be
* followed (on disk) by an indirect block.
* To store the locations of file's data ext2 uses a data structure common
* for UNIX filesystems - tree of pointers anchored in the inode, with
* data blocks at leaves and indirect blocks in intermediate nodes.
* This function translates the block number into path in that tree -
* return value is the path length and @offsets[n] is the offset of
* pointer to (n+1)th node in the nth one. If @block is out of range
* (negative or too large) warning is printed and zero returned.
*
* Note: function doesn't find node addresses, so no IO is needed. All
* we need to know is the capacity of indirect blocks (taken from the
* inode->i_sb).
*/
/*
* Portability note: the last comparison (check that we fit into triple
* indirect block) is spelled differently, because otherwise on an
* architecture with 32-bit longs and 8Kb pages we might get into trouble
* if our filesystem had 8Kb blocks. We might use long long, but that would
* kill us on x86. Oh, well, at least the sign propagation does not matter -
* i_block would have to be negative in the very beginning, so we would not
* get there at all.
*/
static int ext2_block_to_path(struct inode *inode,
long i_block, int offsets[4], int *boundary)
{
int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
const long direct_blocks = EXT2_NDIR_BLOCKS,
indirect_blocks = ptrs,
double_blocks = (1 << (ptrs_bits * 2));
int n = 0;
int final = 0;
if (i_block < 0) {
ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
} else if (i_block < direct_blocks) {
offsets[n++] = i_block;
final = direct_blocks;
} else if ( (i_block -= direct_blocks) < indirect_blocks) {
offsets[n++] = EXT2_IND_BLOCK;
offsets[n++] = i_block;
final = ptrs;
} else if ((i_block -= indirect_blocks) < double_blocks) {
offsets[n++] = EXT2_DIND_BLOCK;
offsets[n++] = i_block >> ptrs_bits;
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
offsets[n++] = EXT2_TIND_BLOCK;
offsets[n++] = i_block >> (ptrs_bits * 2);
offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else {
ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
}
if (boundary)
*boundary = (i_block & (ptrs - 1)) == (final - 1);
return n;
}
/**
* ext2_get_branch - read the chain of indirect blocks leading to data
* @inode: inode in question
* @depth: depth of the chain (1 - direct pointer, etc.)
* @offsets: offsets of pointers in inode/indirect blocks
* @chain: place to store the result
* @err: here we store the error value
*
* Function fills the array of triples <key, p, bh> and returns %NULL
* if everything went OK or the pointer to the last filled triple
* (incomplete one) otherwise. Upon the return chain[i].key contains
* the number of (i+1)-th block in the chain (as it is stored in memory,
* i.e. little-endian 32-bit), chain[i].p contains the address of that
* number (it points into struct inode for i==0 and into the bh->b_data
* for i>0) and chain[i].bh points to the buffer_head of i-th indirect
* block for i>0 and NULL for i==0. In other words, it holds the block
* numbers of the chain, addresses they were taken from (and where we can
* verify that chain did not change) and buffer_heads hosting these
* numbers.
*
* Function stops when it stumbles upon zero pointer (absent block)
* (pointer to last triple returned, *@err == 0)
* or when it gets an IO error reading an indirect block
* (ditto, *@err == -EIO)
* or when it notices that chain had been changed while it was reading
* (ditto, *@err == -EAGAIN)
* or when it reads all @depth-1 indirect blocks successfully and finds
* the whole chain, all way to the data (returns %NULL, *err == 0).
*/
static Indirect *ext2_get_branch(struct inode *inode,
int depth,
int *offsets,
Indirect chain[4],
int *err)
{
struct super_block *sb = inode->i_sb;
Indirect *p = chain;
struct buffer_head *bh;
*err = 0;
/* i_data is not going away, no lock needed */
add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
if (!p->key)
goto no_block;
while (--depth) {
bh = sb_bread(sb, le32_to_cpu(p->key));
if (!bh)
goto failure;
read_lock(&EXT2_I(inode)->i_meta_lock);
if (!verify_chain(chain, p))
goto changed;
add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
read_unlock(&EXT2_I(inode)->i_meta_lock);
if (!p->key)
goto no_block;
}
return NULL;
changed:
read_unlock(&EXT2_I(inode)->i_meta_lock);
brelse(bh);
*err = -EAGAIN;
goto no_block;
failure:
*err = -EIO;
no_block:
return p;
}
/**
* ext2_find_near - find a place for allocation with sufficient locality
* @inode: owner
* @ind: descriptor of indirect block.
*
* This function returns the prefered place for block allocation.
* It is used when heuristic for sequential allocation fails.
* Rules are:
* + if there is a block to the left of our position - allocate near it.
* + if pointer will live in indirect block - allocate near that block.
* + if pointer will live in inode - allocate in the same cylinder group.
*
* In the latter case we colour the starting block by the callers PID to
* prevent it from clashing with concurrent allocations for a different inode
* in the same block group. The PID is used here so that functionally related
* files will be close-by on-disk.
*
* Caller must make sure that @ind is valid and will stay that way.
*/
static unsigned long ext2_find_near(struct inode *inode, Indirect *ind)
{
struct ext2_inode_info *ei = EXT2_I(inode);
__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
__le32 *p;
unsigned long bg_start;
unsigned long colour;
/* Try to find previous block */
for (p = ind->p - 1; p >= start; p--)
if (*p)
return le32_to_cpu(*p);
/* No such thing, so let's try location of indirect block */
if (ind->bh)
return ind->bh->b_blocknr;
/*
* It is going to be refered from inode itself? OK, just put it into
* the same cylinder group then.
*/
bg_start = (ei->i_block_group * EXT2_BLOCKS_PER_GROUP(inode->i_sb)) +
le32_to_cpu(EXT2_SB(inode->i_sb)->s_es->s_first_data_block);
colour = (current->pid % 16) *
(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
return bg_start + colour;
}
/**
* ext2_find_goal - find a prefered place for allocation.
* @inode: owner
* @block: block we want
* @chain: chain of indirect blocks
* @partial: pointer to the last triple within a chain
* @goal: place to store the result.
*
* Normally this function find the prefered place for block allocation,
* stores it in *@goal and returns zero. If the branch had been changed
* under us we return -EAGAIN.
*/
static inline int ext2_find_goal(struct inode *inode,
long block,
Indirect chain[4],
Indirect *partial,
unsigned long *goal)
{
struct ext2_inode_info *ei = EXT2_I(inode);
write_lock(&ei->i_meta_lock);
if ((block == ei->i_next_alloc_block + 1) && ei->i_next_alloc_goal) {
ei->i_next_alloc_block++;
ei->i_next_alloc_goal++;
}
if (verify_chain(chain, partial)) {
/*
* try the heuristic for sequential allocation,
* failing that at least try to get decent locality.
*/
if (block == ei->i_next_alloc_block)
*goal = ei->i_next_alloc_goal;
if (!*goal)
*goal = ext2_find_near(inode, partial);
write_unlock(&ei->i_meta_lock);
return 0;
}
write_unlock(&ei->i_meta_lock);
return -EAGAIN;
}
/**
* ext2_alloc_branch - allocate and set up a chain of blocks.
* @inode: owner
* @num: depth of the chain (number of blocks to allocate)
* @offsets: offsets (in the blocks) to store the pointers to next.
* @branch: place to store the chain in.
*
* This function allocates @num blocks, zeroes out all but the last one,
* links them into chain and (if we are synchronous) writes them to disk.
* In other words, it prepares a branch that can be spliced onto the
* inode. It stores the information about that chain in the branch[], in
* the same format as ext2_get_branch() would do. We are calling it after
* we had read the existing part of chain and partial points to the last
* triple of that (one with zero ->key). Upon the exit we have the same
* picture as after the successful ext2_get_block(), excpet that in one
* place chain is disconnected - *branch->p is still zero (we did not
* set the last link), but branch->key contains the number that should
* be placed into *branch->p to fill that gap.
*
* If allocation fails we free all blocks we've allocated (and forget
* their buffer_heads) and return the error value the from failed
* ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
* as described above and return 0.
*/
static int ext2_alloc_branch(struct inode *inode,
int num,
unsigned long goal,
int *offsets,
Indirect *branch)
{
int blocksize = inode->i_sb->s_blocksize;
int n = 0;
int err;
int i;
int parent = ext2_alloc_block(inode, goal, &err);
branch[0].key = cpu_to_le32(parent);
if (parent) for (n = 1; n < num; n++) {
struct buffer_head *bh;
/* Allocate the next block */
int nr = ext2_alloc_block(inode, parent, &err);
if (!nr)
break;
branch[n].key = cpu_to_le32(nr);
/*
* Get buffer_head for parent block, zero it out and set
* the pointer to new one, then send parent to disk.
*/
bh = sb_getblk(inode->i_sb, parent);
if (!bh) {
err = -EIO;
break;
}
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
branch[n].bh = bh;
branch[n].p = (__le32 *) bh->b_data + offsets[n];
*branch[n].p = branch[n].key;
set_buffer_uptodate(bh);
unlock_buffer(bh);
mark_buffer_dirty_inode(bh, inode);
/* We used to sync bh here if IS_SYNC(inode).
* But we now rely upon generic_osync_inode()
* and b_inode_buffers. But not for directories.
*/
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
sync_dirty_buffer(bh);
parent = nr;
}
if (n == num)
return 0;
/* Allocation failed, free what we already allocated */
for (i = 1; i < n; i++)
bforget(branch[i].bh);
for (i = 0; i < n; i++)
ext2_free_blocks(inode, le32_to_cpu(branch[i].key), 1);
return err;
}
/**
* ext2_splice_branch - splice the allocated branch onto inode.
* @inode: owner
* @block: (logical) number of block we are adding
* @chain: chain of indirect blocks (with a missing link - see
* ext2_alloc_branch)
* @where: location of missing link
* @num: number of blocks we are adding
*
* This function verifies that chain (up to the missing link) had not
* changed, fills the missing link and does all housekeeping needed in
* inode (->i_blocks, etc.). In case of success we end up with the full
* chain to new block and return 0. Otherwise (== chain had been changed)
* we free the new blocks (forgetting their buffer_heads, indeed) and
* return -EAGAIN.
*/
static inline int ext2_splice_branch(struct inode *inode,
long block,
Indirect chain[4],
Indirect *where,
int num)
{
struct ext2_inode_info *ei = EXT2_I(inode);
int i;
/* Verify that place we are splicing to is still there and vacant */
write_lock(&ei->i_meta_lock);
if (!verify_chain(chain, where-1) || *where->p)
goto changed;
/* That's it */
*where->p = where->key;
ei->i_next_alloc_block = block;
ei->i_next_alloc_goal = le32_to_cpu(where[num-1].key);
write_unlock(&ei->i_meta_lock);
/* We are done with atomic stuff, now do the rest of housekeeping */
inode->i_ctime = CURRENT_TIME_SEC;
/* had we spliced it onto indirect block? */
if (where->bh)
mark_buffer_dirty_inode(where->bh, inode);
mark_inode_dirty(inode);
return 0;
changed:
write_unlock(&ei->i_meta_lock);
for (i = 1; i < num; i++)
bforget(where[i].bh);
for (i = 0; i < num; i++)
ext2_free_blocks(inode, le32_to_cpu(where[i].key), 1);
return -EAGAIN;
}
/*
* Allocation strategy is simple: if we have to allocate something, we will
* have to go the whole way to leaf. So let's do it before attaching anything
* to tree, set linkage between the newborn blocks, write them if sync is
* required, recheck the path, free and repeat if check fails, otherwise
* set the last missing link (that will protect us from any truncate-generated
* removals - all blocks on the path are immune now) and possibly force the
* write on the parent block.
* That has a nice additional property: no special recovery from the failed
* allocations is needed - we simply release blocks and do not touch anything
* reachable from inode.
*/
int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
{
int err = -EIO;
int offsets[4];
Indirect chain[4];
Indirect *partial;
unsigned long goal;
int left;
int boundary = 0;
int depth = ext2_block_to_path(inode, iblock, offsets, &boundary);
if (depth == 0)
goto out;
reread:
partial = ext2_get_branch(inode, depth, offsets, chain, &err);
/* Simplest case - block found, no allocation needed */
if (!partial) {
got_it:
map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
if (boundary)
set_buffer_boundary(bh_result);
/* Clean up and exit */
partial = chain+depth-1; /* the whole chain */
goto cleanup;
}
/* Next simple case - plain lookup or failed read of indirect block */
if (!create || err == -EIO) {
cleanup:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
out:
return err;
}
/*
* Indirect block might be removed by truncate while we were
* reading it. Handling of that case (forget what we've got and
* reread) is taken out of the main path.
*/
if (err == -EAGAIN)
goto changed;
goal = 0;
if (ext2_find_goal(inode, iblock, chain, partial, &goal) < 0)
goto changed;
left = (chain + depth) - partial;
err = ext2_alloc_branch(inode, left, goal,
offsets+(partial-chain), partial);
if (err)
goto cleanup;
if (ext2_use_xip(inode->i_sb)) {
/*
* we need to clear the block
*/
err = ext2_clear_xip_target (inode,
le32_to_cpu(chain[depth-1].key));
if (err)
goto cleanup;
}
if (ext2_splice_branch(inode, iblock, chain, partial, left) < 0)
goto changed;
set_buffer_new(bh_result);
goto got_it;
changed:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
goto reread;
}
static int ext2_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, ext2_get_block, wbc);
}
static int ext2_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, ext2_get_block);
}
static int
ext2_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
}
static int
ext2_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return block_prepare_write(page,from,to,ext2_get_block);
}
static int
ext2_nobh_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return nobh_prepare_write(page,from,to,ext2_get_block);
}
static int ext2_nobh_writepage(struct page *page,
struct writeback_control *wbc)
{
return nobh_writepage(page, ext2_get_block, wbc);
}
static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping,block,ext2_get_block);
}
static ssize_t
ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t offset, unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, ext2_get_block, NULL);
}
static int
ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
return mpage_writepages(mapping, wbc, ext2_get_block);
}
const struct address_space_operations ext2_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
.writepage = ext2_writepage,
.sync_page = block_sync_page,
.prepare_write = ext2_prepare_write,
.commit_write = generic_commit_write,
.bmap = ext2_bmap,
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
};
const struct address_space_operations ext2_aops_xip = {
.bmap = ext2_bmap,
.get_xip_page = ext2_get_xip_page,
};
const struct address_space_operations ext2_nobh_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
.writepage = ext2_nobh_writepage,
.sync_page = block_sync_page,
.prepare_write = ext2_nobh_prepare_write,
.commit_write = nobh_commit_write,
.bmap = ext2_bmap,
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
};
/*
* Probably it should be a library function... search for first non-zero word
* or memcmp with zero_page, whatever is better for particular architecture.
* Linus?
*/
static inline int all_zeroes(__le32 *p, __le32 *q)
{
while (p < q)
if (*p++)
return 0;
return 1;
}
/**
* ext2_find_shared - find the indirect blocks for partial truncation.
* @inode: inode in question
* @depth: depth of the affected branch
* @offsets: offsets of pointers in that branch (see ext2_block_to_path)
* @chain: place to store the pointers to partial indirect blocks
* @top: place to the (detached) top of branch
*
* This is a helper function used by ext2_truncate().
*
* When we do truncate() we may have to clean the ends of several indirect
* blocks but leave the blocks themselves alive. Block is partially
* truncated if some data below the new i_size is refered from it (and
* it is on the path to the first completely truncated data block, indeed).
* We have to free the top of that path along with everything to the right
* of the path. Since no allocation past the truncation point is possible
* until ext2_truncate() finishes, we may safely do the latter, but top
* of branch may require special attention - pageout below the truncation
* point might try to populate it.
*
* We atomically detach the top of branch from the tree, store the block
* number of its root in *@top, pointers to buffer_heads of partially
* truncated blocks - in @chain[].bh and pointers to their last elements
* that should not be removed - in @chain[].p. Return value is the pointer
* to last filled element of @chain.
*
* The work left to caller to do the actual freeing of subtrees:
* a) free the subtree starting from *@top
* b) free the subtrees whose roots are stored in
* (@chain[i].p+1 .. end of @chain[i].bh->b_data)
* c) free the subtrees growing from the inode past the @chain[0].p
* (no partially truncated stuff there).
*/
static Indirect *ext2_find_shared(struct inode *inode,
int depth,
int offsets[4],
Indirect chain[4],
__le32 *top)
{
Indirect *partial, *p;
int k, err;
*top = 0;
for (k = depth; k > 1 && !offsets[k-1]; k--)
;
partial = ext2_get_branch(inode, k, offsets, chain, &err);
if (!partial)
partial = chain + k-1;
/*
* If the branch acquired continuation since we've looked at it -
* fine, it should all survive and (new) top doesn't belong to us.
*/
write_lock(&EXT2_I(inode)->i_meta_lock);
if (!partial->key && *partial->p) {
write_unlock(&EXT2_I(inode)->i_meta_lock);
goto no_top;
}
for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
;
/*
* OK, we've found the last block that must survive. The rest of our
* branch should be detached before unlocking. However, if that rest
* of branch is all ours and does not grow immediately from the inode
* it's easier to cheat and just decrement partial->p.
*/
if (p == chain + k - 1 && p > chain) {
p->p--;
} else {
*top = *p->p;
*p->p = 0;
}
write_unlock(&EXT2_I(inode)->i_meta_lock);
while(partial > p)
{
brelse(partial->bh);
partial--;
}
no_top:
return partial;
}
/**
* ext2_free_data - free a list of data blocks
* @inode: inode we are dealing with
* @p: array of block numbers
* @q: points immediately past the end of array
*
* We are freeing all blocks refered from that array (numbers are
* stored as little-endian 32-bit) and updating @inode->i_blocks
* appropriately.
*/
static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
{
unsigned long block_to_free = 0, count = 0;
unsigned long nr;
for ( ; p < q ; p++) {
nr = le32_to_cpu(*p);
if (nr) {
*p = 0;
/* accumulate blocks to free if they're contiguous */
if (count == 0)
goto free_this;
else if (block_to_free == nr - count)
count++;
else {
mark_inode_dirty(inode);
ext2_free_blocks (inode, block_to_free, count);
free_this:
block_to_free = nr;
count = 1;
}
}
}
if (count > 0) {
mark_inode_dirty(inode);
ext2_free_blocks (inode, block_to_free, count);
}
}
/**
* ext2_free_branches - free an array of branches
* @inode: inode we are dealing with
* @p: array of block numbers
* @q: pointer immediately past the end of array
* @depth: depth of the branches to free
*
* We are freeing all blocks refered from these branches (numbers are
* stored as little-endian 32-bit) and updating @inode->i_blocks
* appropriately.
*/
static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
{
struct buffer_head * bh;
unsigned long nr;
if (depth--) {
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
for ( ; p < q ; p++) {
nr = le32_to_cpu(*p);
if (!nr)
continue;
*p = 0;
bh = sb_bread(inode->i_sb, nr);
/*
* A read failure? Report error and clear slot
* (should be rare).
*/
if (!bh) {
ext2_error(inode->i_sb, "ext2_free_branches",
"Read failure, inode=%ld, block=%ld",
inode->i_ino, nr);
continue;
}
ext2_free_branches(inode,
(__le32*)bh->b_data,
(__le32*)bh->b_data + addr_per_block,
depth);
bforget(bh);
ext2_free_blocks(inode, nr, 1);
mark_inode_dirty(inode);
}
} else
ext2_free_data(inode, p, q);
}
void ext2_truncate (struct inode * inode)
{
__le32 *i_data = EXT2_I(inode)->i_data;
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
int offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n;
long iblock;
unsigned blocksize;
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)))
return;
if (ext2_inode_is_fast_symlink(inode))
return;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
ext2_discard_prealloc(inode);
blocksize = inode->i_sb->s_blocksize;
iblock = (inode->i_size + blocksize-1)
>> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
if (mapping_is_xip(inode->i_mapping))
xip_truncate_page(inode->i_mapping, inode->i_size);
else if (test_opt(inode->i_sb, NOBH))
nobh_truncate_page(inode->i_mapping, inode->i_size);
else
block_truncate_page(inode->i_mapping,
inode->i_size, ext2_get_block);
n = ext2_block_to_path(inode, iblock, offsets, NULL);
if (n == 0)
return;
if (n == 1) {
ext2_free_data(inode, i_data+offsets[0],
i_data + EXT2_NDIR_BLOCKS);
goto do_indirects;
}
partial = ext2_find_shared(inode, n, offsets, chain, &nr);
/* Kill the top of shared branch (already detached) */
if (nr) {
if (partial == chain)
mark_inode_dirty(inode);
else
mark_buffer_dirty_inode(partial->bh, inode);
ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
}
/* Clear the ends of indirect blocks on the shared branch */
while (partial > chain) {
ext2_free_branches(inode,
partial->p + 1,
(__le32*)partial->bh->b_data+addr_per_block,
(chain+n-1) - partial);
mark_buffer_dirty_inode(partial->bh, inode);
brelse (partial->bh);
partial--;
}
do_indirects:
/* Kill the remaining (whole) subtrees */
switch (offsets[0]) {
default:
nr = i_data[EXT2_IND_BLOCK];
if (nr) {
i_data[EXT2_IND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 1);
}
case EXT2_IND_BLOCK:
nr = i_data[EXT2_DIND_BLOCK];
if (nr) {
i_data[EXT2_DIND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 2);
}
case EXT2_DIND_BLOCK:
nr = i_data[EXT2_TIND_BLOCK];
if (nr) {
i_data[EXT2_TIND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 3);
}
case EXT2_TIND_BLOCK:
;
}
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
if (inode_needs_sync(inode)) {
sync_mapping_buffers(inode->i_mapping);
ext2_sync_inode (inode);
} else {
mark_inode_dirty(inode);
}
}
static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
struct buffer_head **p)
{
struct buffer_head * bh;
unsigned long block_group;
unsigned long block;
unsigned long offset;
struct ext2_group_desc * gdp;
*p = NULL;
if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
goto Einval;
block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
gdp = ext2_get_group_desc(sb, block_group, &bh);
if (!gdp)
goto Egdp;
/*
* Figure out the offset within the block group inode table
*/
offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
block = le32_to_cpu(gdp->bg_inode_table) +
(offset >> EXT2_BLOCK_SIZE_BITS(sb));
if (!(bh = sb_bread(sb, block)))
goto Eio;
*p = bh;
offset &= (EXT2_BLOCK_SIZE(sb) - 1);
return (struct ext2_inode *) (bh->b_data + offset);
Einval:
ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
(unsigned long) ino);
return ERR_PTR(-EINVAL);
Eio:
ext2_error(sb, "ext2_get_inode",
"unable to read inode block - inode=%lu, block=%lu",
(unsigned long) ino, block);
Egdp:
return ERR_PTR(-EIO);
}
void ext2_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT2_I(inode)->i_flags;
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT2_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT2_APPEND_FL)
inode->i_flags |= S_APPEND;
if (flags & EXT2_IMMUTABLE_FL)
inode->i_flags |= S_IMMUTABLE;
if (flags & EXT2_NOATIME_FL)
inode->i_flags |= S_NOATIME;
if (flags & EXT2_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
}
void ext2_read_inode (struct inode * inode)
{
struct ext2_inode_info *ei = EXT2_I(inode);
ino_t ino = inode->i_ino;
struct buffer_head * bh;
struct ext2_inode * raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
int n;
#ifdef CONFIG_EXT2_FS_POSIX_ACL
ei->i_acl = EXT2_ACL_NOT_CACHED;
ei->i_default_acl = EXT2_ACL_NOT_CACHED;
#endif
if (IS_ERR(raw_inode))
goto bad_inode;
inode->i_mode = le16_to_cpu(raw_inode->i_mode);
inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
if (!(test_opt (inode->i_sb, NO_UID32))) {
inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
}
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
inode->i_size = le32_to_cpu(raw_inode->i_size);
inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime);
inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime);
inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime);
inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
/* We now have enough fields to check if the inode was active or not.
* This is needed because nfsd might try to access dead inodes
* the test is that same one that e2fsck uses
* NeilBrown 1999oct15
*/
if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
/* this inode is deleted */
brelse (bh);
goto bad_inode;
}
inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
ei->i_frag_no = raw_inode->i_frag;
ei->i_frag_size = raw_inode->i_fsize;
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
ei->i_dir_acl = 0;
if (S_ISREG(inode->i_mode))
inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
else
ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
ei->i_dtime = 0;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_state = 0;
ei->i_next_alloc_block = 0;
ei->i_next_alloc_goal = 0;
ei->i_prealloc_count = 0;
ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
ei->i_dir_start_lookup = 0;
/*
* NOTE! The in-memory inode i_data array is in little-endian order
* even on big-endian machines: we do NOT byteswap the block numbers!
*/
for (n = 0; n < EXT2_N_BLOCKS; n++)
ei->i_data[n] = raw_inode->i_block[n];
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext2_file_inode_operations;
if (ext2_use_xip(inode->i_sb)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_file_operations;
}
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
} else if (S_ISLNK(inode->i_mode)) {
if (ext2_inode_is_fast_symlink(inode))
inode->i_op = &ext2_fast_symlink_inode_operations;
else {
inode->i_op = &ext2_symlink_inode_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
}
} else {
inode->i_op = &ext2_special_inode_operations;
if (raw_inode->i_block[0])
init_special_inode(inode, inode->i_mode,
old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
else
init_special_inode(inode, inode->i_mode,
new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
}
brelse (bh);
ext2_set_inode_flags(inode);
return;
bad_inode:
make_bad_inode(inode);
return;
}
static int ext2_update_inode(struct inode * inode, int do_sync)
{
struct ext2_inode_info *ei = EXT2_I(inode);
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
uid_t uid = inode->i_uid;
gid_t gid = inode->i_gid;
struct buffer_head * bh;
struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
int n;
int err = 0;
if (IS_ERR(raw_inode))
return -EIO;
/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT2_STATE_NEW)
memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
if (!(test_opt(sb, NO_UID32))) {
raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
/*
* Fix up interoperability with old kernels. Otherwise, old inodes get
* re-used with the upper 16 bits of the uid/gid intact
*/
if (!ei->i_dtime) {
raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
} else {
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
} else {
raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
raw_inode->i_size = cpu_to_le32(inode->i_size);
raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
raw_inode->i_flags = cpu_to_le32(ei->i_flags);
raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
raw_inode->i_frag = ei->i_frag_no;
raw_inode->i_fsize = ei->i_frag_size;
raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
if (!S_ISREG(inode->i_mode))
raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
else {
raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
if (inode->i_size > 0x7fffffffULL) {
if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
EXT2_SB(sb)->s_es->s_rev_level ==
cpu_to_le32(EXT2_GOOD_OLD_REV)) {
/* If this is the first large file
* created, add a flag to the superblock.
*/
lock_kernel();
ext2_update_dynamic_rev(sb);
EXT2_SET_RO_COMPAT_FEATURE(sb,
EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
unlock_kernel();
ext2_write_super(sb);
}
}
}
raw_inode->i_generation = cpu_to_le32(inode->i_generation);
if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
if (old_valid_dev(inode->i_rdev)) {
raw_inode->i_block[0] =
cpu_to_le32(old_encode_dev(inode->i_rdev));
raw_inode->i_block[1] = 0;
} else {
raw_inode->i_block[0] = 0;
raw_inode->i_block[1] =
cpu_to_le32(new_encode_dev(inode->i_rdev));
raw_inode->i_block[2] = 0;
}
} else for (n = 0; n < EXT2_N_BLOCKS; n++)
raw_inode->i_block[n] = ei->i_data[n];
mark_buffer_dirty(bh);
if (do_sync) {
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh)) {
printk ("IO error syncing ext2 inode [%s:%08lx]\n",
sb->s_id, (unsigned long) ino);
err = -EIO;
}
}
ei->i_state &= ~EXT2_STATE_NEW;
brelse (bh);
return err;
}
int ext2_write_inode(struct inode *inode, int wait)
{
return ext2_update_inode(inode, wait);
}
int ext2_sync_inode(struct inode *inode)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = 0, /* sys_fsync did this */
};
return sync_inode(inode, &wbc);
}
int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
int error;
error = inode_change_ok(inode, iattr);
if (error)
return error;
if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
(iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
error = DQUOT_TRANSFER(inode, iattr) ? -EDQUOT : 0;
if (error)
return error;
}
error = inode_setattr(inode, iattr);
if (!error && (iattr->ia_valid & ATTR_MODE))
error = ext2_acl_chmod(inode);
return error;
}